1. Field of the Invention
The present invention relates in general to computer file systems, and more particularly to retrieving, storing, and using file attributes from one file system in another file system.
2. Description of the Related Art
Data processing systems usually store information in files. A file is a named set or collection of records, logical records, data, or information stored, retrieved, or processed as a unit. Such a file may have various characteristics, and these characteristics may be described by an attribute. An attribute is a specific characteristic that identifies and describes properties of a managed object. The characteristic can be determined, and possibly changed, through operations on the managed object. For example, a file may have attributes that define it as hidden or read-only. Thus, any of the attributes that describe the characteristics of a file are known as file attributes.
Not all file systems share a common identical set of file attributes. For example, a first file system may provide file attributes such as read-only or hidden; whereas, a second file system may not support these file attributes. If a user of the second file system attempts to access files on the first file system, then the second file system will not recognize or appropriately process the file attributes from the first file system.
More specifically, in workstation file systems, externally accessible file attributes are those that can be queried and/or modified by an application programmer using a public application programming interface (PAPI) as opposed to internal functions of the operating system. These are normally implemented as bits that are set on or off, or as integer values in fixed size multi-bit fields such as a four-byte integer. The number of attributes is limited by implementation of the native workstation file system. Installable distributed file systems (that is, file systems that can access files on remote computers) can present difficulties when attempting to convey file attributes that are not present in the local native workstation file system.
Conventional file attributes in workstation operating systems such as the WINDOWS 95™ operating system (releases 1 and 2) and the WINDOWS 98™ operating system (first and second editions) have been carried over from earlier operating systems such as Disk Operating System (DOS) (MICROSOFT, WINDOWS, WINDOWS NT, and the WINDOWS logo are trademarks of Microsoft Corporation in the United States, other countries, or both.). Modern operating systems such as the OS/2® operating system (release 1 through Warp 4) and the WINDOWS NT™ operating system (version 3.1 through 4.0) introduced “extended” attributes that are represented by an extended set of flags or integer values. Remote host file attributes (such as record format, logical record length, or sequence numbers in MVS® data sets (version 1 through ESA)) can be used by the workstation tools (such as workstation textual editors, for example the IBM® LPEX editor (versions 1 through 4)) to provide additional information to the user and additional functionality to the tools. (IBM®, MVS®, and OS/2® are registered trademarks of International Business Machines Corporation in the United States, other countries, or both.). For example, a textual editor can detect use of sequence numbers in an MVS file and adjust its behavior so that editing of the sequence number area in the file is prohibited by the user. The editor then can automatically adjust sequence numbers when the lines in the file are added or deleted on the workstation. Remote file attributes cannot be represented with workstation file system's conventional or extended file attributes. Existing methods of providing extended information in workstation files normally apply only to files that physically reside on the workstation file systems. Such attributes are normally stored as integral part of the file. Those files are textual files whose formats are specific to the editors that use those formats. For example, the MICROSOFT™ WORD editor (versions 1 through 9) uses its own file format, and the LOTUS® WORD PRO® editor (versions 1 through 9) uses yet another format (LOTUS® and WORD PRO® are registered trademarks of Lotus Development Corporation.). Those formats cannot be applied to the remote host files because those files reside on the remote host and are not cached on the workstation in any useable form. The formats and textual encoding on the host are host specific, for example, Extended Binary-Coded Decimal Interchange Code (EBCDIC) encoding on an IBM S/390® computer system (S/390® is a registered trademark of International Business Machines Corporation in the United States, other countries, or both.
Thus, there is a clearly felt need for a method, system, and program product for storing and accessing remote file attributes on a workstation's installable file system.